Crangonyctidae Bousfield, 1973

Type genus. Crangonyx Bate, 1859.

Diagnostic description. Body laterally compressed or subcylindrical. Eyes well developed or absent, if present then round, ovoid or subrectangular. Antennae 1–2 calceoli crangonyctoid (type 9). Antenna 1 longer than antenna 2; peduncular article 1 subequal to, or longer than article 2; article 2 longer than article 3; article 3 shorter than article 1; peduncular articles 1–2 not geniculate; accessory flagellum minute. Antenna 2 peduncular article 1 enlarged, bulbous. Mandible molar triturative; palp symmetrical. Maxilla 1 basal endite setose along medial margin or apically setose; palps symmetrical. Maxilla 2 basal endite with oblique setal row. Labium inner lobes present. Coxal gills number and sequence [not known], stalked (with proximal restriction or complete suture); sternal gills present, simple; sternal blisters absent; oostegites fringing setae simple. Gnathopod 1 subchelate; similar in males and females (not sexually dimorphic); smaller (or weaker) than or similar in size to gnathopod 2; propodus palm with row or rows of simple or bifid robust setae along palmar margin. Gnathopod 2 subchelate; similar in males and females (not sexually dimorphic); carpus not produced along posterior margin of propodus, projecting between merus and propodus. Pereopods 3–4 not sexually dimorphic. Pereopod 4 with well developed posteroventral lobe or without posteroventral lobe. Pereopod 5 shorter than, subequal in length to, or longer than pereopod 6; coxa with large anteroventral lobe or with small anteroventral lobe. Pereopod 7 shorter than, subequal in length to, or longer than pereopod 5. Pleonites 1–3 without dorsal carinae. Urosomites 1–3 free; without slender or robust dorsal setae. Urosomite 1 with or without large distoventral robust seta. Urosomite 2 without dorsal setae. Uropod 1 with 1 or 2 basofacial robust setae or without basofacial robust setae. Uropod 3 not sexually dimorphic; biramous, uniramous or rami absent, without plumose setae; endopod minute or shorter than exopod. Telson moderately cleft, notched, emarginate or entire; dorsal or lateral robust setae absent; apical robust setae present.

Habitat. Freshwater, hypogean and epigean.

Included genera. Bactrurus Hay, 1902; Crangonyx Bate, 1859; Lyurella Derzhavin, 1939; Pachypodacrangonyx Boutin & Coineau, 1987; Stygobromus Cope, 1872; Stygonyx Bousfield & Holsinger, 1989; Synurella Wrzesniowski, 1877.

Distribution. Holarctic.